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I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.

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Session TSP11: Performance of the TotalStorage DS8000, Speaker: Lee La Frese Of course a new disk controller from IBM is going to appear awesome. :-) DS8000 is no exception. Currently 2-way and 4-way POWER5 processors. Statement of Direction for an 8-way machine. POWER5 can go up to a 64-way. I/O access density has levelled out over the last five years (2000 to 2005), having historically decreased... [More]

Session ZP05: Parallel Sysplex Tuning, Presenter: Joan Kelley Joan gave a good summary of CF levels and general-but-detailed tuning recommendations. Enhanced Patch Apply on z890 and z990 allows different CF levels on the same CEC. But a customer suggested that in their environment re-IPLing one of the CF LPARs brought it automatically up to the newer level. Joan will try to reproduce in the lab.... [More]

Session z05: z/OS Sysprog Goody Bag, Presenter: Bob Rogers Bob is always good value. This time was no exception. Consoles Restructure undertaken because a problem cause analysis for Parallel Sysplex showed Consoles as being the weakest link. Also there was a need to remove some constraints, such as the 1-byte console ID, plus the need to reduce the scaling inhibitor of metadata in large sysplexes.... [More]

I always look forward to the publication of the "DB2 Performance Topics" red book for each release of DB2. This time was no exception. Except: I was lucky enough to participate in reviewing this one - for Version 8. Most of the credit, though, goes to a great team of residents and developers (my role being minor). So here's a link to a draft:... [More]

Here's the gist of an Info APAR on the subject: OA10114. This documentation APAR was taken to enhance the information in the WLM Planning book to more cleary state that the intent of the WLM Managed Batch Initiator Balancing enhancement is not to evenly distribute the batch workload among systems in the sysplex nor to equalize the CPU utilization across systems in the sysplex. ... [More]

PK01266 enables parallelism in Star Join under an additional set of circumstances: From the APAR Database: STAR JOIN QUERY ON NON-PARTITIONED FACT TABLE DOES NOT GET CPU PARALLELISM CHOSEN WHEN MULTIPLE CPUS ARE AVAILABLE Starjoin queries with non-partitioned fact table can encounter poor performance since CPU parallelism may not be enabled. The problem is corrected to enable CPU... [More]

In our process we unload the DB2 Catalog with DSNTIAUL and then use the resulting files in our analysis. When prototyping new code, or just plain trying different queries out, we use DFSORT. However VARCHARs pose a bit of a problem, encoded as they are with a 2-byte length and padded with trailing nulls to the VARCHAR's maximum length. If you want to include a record with a specific value shorter... [More]

Would you like to see updates to my blog without having to visit the site on the off chance? If so, read on. Pardon my patronising essentially mainframe people by describing basic web technology but... If you want to get notified when my blog changes you might like to take an RSS feed. RSS clients exist to notify you when this RSS feed pumps something out. I RMBed on the "RSS" icon in the right... [More]

I've had a long and happy association with DFSORT. So here's a link to a document describing the most recent enhancements, which came out in December. http://www-1.ibm.com/servers/storage/support/software/sort/mvs/pdug/ There was also another significant set of changes in February 2003. They are described here: http://www-1.ibm.com/servers/storage/support/software/sort/mvs/uq90053 As I previously... [More]

I'm presenting on a couple of topics at the UKCMG annual conference. This, down the years, has been a great conference and one I look forward to immensely. http://www.ukcmg.org.uk/conference.html My topics are about CPU and DB2 Memory.

I'm fortunate to be presenting at this excellent conference. Here's the URL: http://www-306.ibm.com/services/learning/ites.wss?pageType=page&c=a0006121 There are many fine presentations on the agenda. My presentations are in the areas of DB2 Memory, CPU Management, "Modern" DB2 Applications' performance, and DFSORT. All of these are significantly updated from previous conferences, and the CPU one... [More]

For me that isn't really the question - I've been blogging inside IBM for about a year now. And the benefits are well-known to me. So welcome to my customer-facing blog. I do like to mention client situations. But (especially as I'm helping develop IBM's blogging guidelines in this area) I'd like to think I will handle client situations sensitively: As most people who I've worked for know I don't... [More]

… or probably more. I was going to use “Send In The Clones” but I’ve already used it - and someone who shall remain nameless once misremembered it as “Let There Be Clones”. Let there be clones, indeed. So, how do I detect cloned CICS regions, for example? (And if you want to know why I’m asking that question now it’s an enforced rereading of
CICS... [More]

“Mobile” appears to be “flavour of the month” right now, and this week at System z Technical University it has certainly been a topic in evidence, whether it’s discussions in the breaks, sessions on software pricing, or sessions on Mobile-enabling technology. I don’t intend in this post to discuss any of these. Instead I want to talk about the types of users... [More]

h3, h4, p {
margin-top: 2em;
margin-bottom: 2em;
} I’ve been meaning to write about MEMLIMIT and its importance for some time. [1] But it’s a moving target. So either there’s no good time to talk about it or lots of good times. So let me discuss it now and then again later as necessary. [2] So timing a post on MEMLIMIT is like choosing a wave to catch: In this case the... [More]